The GEM theory is an old idea that emerges from attempts to unify the theories of gravity and electromagnetism [1]}, [2]}, [3]}, [4]}, [5]}, [6]}. The foundation of this theory lies in the similarities between gravitational and electromagnetic forces. There are three different approaches to investigating GEM theory: (i) considering the Einstein and Maxwell equations in the weak field approach [7]}; (ii) using tidal tensors [8]} and (iii) using the Weyl tensor and its decomposition into components [9]}. Weyl components are designated as gravitoelectric and gravitomagnetic fields. These names are associated with the fact that in weak field approximation the Einstein equations take a form similar to Maxwell equations of electromagnetism. Thus, the interaction between moving masses can be described in terms of forces due to two fields: the gravitoelectric which is analogous to the electric field, and the gravitomagnetic field which is analogous to the magnetic field of classical electromagnetism. Some effects of the GEM theory have been experimentally confirmed [10]}, [11]}.
